The Khashoggi family visited this dry valley almost 10 years ago and found it akin to their own desert kingdom. Liking what they saw, the Saudis bankrolled two keystone developments on the Salt Lake cityscape with initial investments of more than $20 million.

The projects - an inner-city complex and a giant industrial park - were initiated by Khashoggi brothers Adnan and Essam, who operate their group of companies called Triad out of Saudi Arabia, while Adnan's son, Muhammad, goes to school in luxury here, keeping an eye on the family fortunes.

Not since Brigham Young led the Mormons to this valley 135 years ago - to make it ''blossom like a rose'' - have people here seen such rapid investment in private business as in the Khashoggi projects.

The five-year-old industrial park, called the Salt Lake International Center, has taken in over 65 well-known manufacturing and service companies with a total

The Park's real value, however, may be in pioneering growth in the arid, desolate northwestern part of the valley, pulling away from the high ground of the overcrowded, well-watered Wasatch Front hills.

The Khashoggis are also symbols of city's continuing need for outside money. ''The risk capital is just not here,'' says Emanuel A. Floor, president of Triad Utah.

They are also backing a $410 million complex called the Gathering Place (an old Mormon phrase), which will play a key role in reviving the city's shabby and empty lots near the Union Pacific railroad station. The Gathering Place will cover nearly three blocks, combining two 40-story mirrored offices and condos with shopping arcades in an architectural style of the 1890s (bricks and arches).

The other parts of Salt Lake City are not remaining idle, however. In the last decade, the Church of Jesus Christ of Latter-day Saints (Mormon) sponsored redevelopment of the northern part of the city around its own Temple Square. Two shopping malls, the Salt Palace stadium, and a striking art and symphony center were built.

''This is mecca to 5 million Mormons,'' says Salt Lake Area Chamber of Commerce director Fred Ball. ''The church helped lead the Temple Square restoration, and it will make sure it won't run down again.''

Salt Lake has never had hard-core slums, but few buildings were put up downtown from 1900 until after World War II. Today, some people suggest the crane has replaced the seagull as the state bird. At least a dozen construction projects are under way.

''I'm not sure I want to see as many skyscrapers shooting up as in our sister city of Denver,'' says Utah Gov. Scott Matheson, who advocates ''managed growth.''

A seesaw of development between the northern and southern parts of the city is now swinging to the south. In the area several blocks south of the Temple Square, once mainly a retail district run by Jewish merchants, a new state office building is planned, as well as hotels, high-rise condominiums, and a strip of offices for professionals. At present, office space costs about half the Denver rate, and developers hope to wrangle Texas oil money gushing into Utah's new explorations.

A behind-the-scenes power in the city is Earl Holding, a young entrepreneur who owns some 30 acres in the south part. Howard Hughes-like in his riches and reclusiveness, the native Utahan turned a Wyoming truck stop known as Little America into an empire of hotels, oil rights, refineries, and now Salt Lake City development.